The purpose of such analyses is to assist the clinician in the interpretation of data provided by sensors providing signals representative of the intracranial pressure (ICP) and linked signals, the blood pressure, the arterial or venous circulation rate and the gas concentrations. They enable the clinician to deduce from them the suitable treatments for the pathology deduced from these information elements. These analyses have been the object of various scientific studies, e.g.:                Lemaire et al., “A computer software for frequency analysis of slow intracranial pressure waves”, Comput. Methods Programs Biomed., 1984, 42, 1-14.        Daley et al., “Fluctuations of intracranial pressure associated with the cardiac cycle”, Journal of Neurosurgery, vol. 11, no. 5, 11-1982, pp. 617-621.        Avezaat et al., “Cerebrospinal fluid pulse pressure and intracranial volume-pressure relationships”, J. Neurol., Neurosurg. and Psych., 1979, 42, 00. 687-700.        Portnoy et al., “Cerebrospinal fluid pulse wave as an indicator of cerebral neuroregulation”, J. Neurosur., vol 56, 5-1982, pp. 666-678.        
Equipment for the acquisition and processing of pressure signals to perform such analyses have been proposed in the state of the art. For example, WO 132076 describes a surveillance device that can determine a physiological parameter in a patient. This device comprises a calibration device configured to provide a calibration signal that is representative of the physiological parameter. A noninvasive sensor is placed on the vessel, with this noninvasive sensor being configured to detect a blood parameter and to produce a signal that is representative of the blood parameter. Thus, there is defined in this context a blood parameter such as pressure, flow rate, volume, velocity, movement and position of the vessel wall and other related parameters. A processor is configured to determine the relationship existing between a characteristic of the excitatory wave received and a characteristic of the physiological parameter.
WO 98/49934 describes a device and a noninvasive method for the measurement of intracranial pressure. The measurement system emits acoustic signals traversing the cranium by means of transmitters and provides an indication of the intracranial pressure as a function of the acoustic signal received after interaction with the brain. Properties such as the impedance of the acoustic transmission, resonance frequency, resonance characteristics, sound velocity and other can be measured and correlated with the intracranial pressure. For example, the acoustic signals have characteristic frequencies of at least 100 kHz, in audible and infrasonic fields. The intensity of the acoustic signal used to measure the intracranial pressure is relatively weak from which derives the possibility of health risks during short or long examinations.
WO 068647 pertains to a method enabling surveillance in a noninvasive manner of the intracranial pressure of a patient. One obtains at least one oscillogram representing a pulsation of an anatomical characteristic of the patient's head, preferable integrating ultrasound reflection traces in a temporal gate corresponding to the reflections of said characteristic. The anatomical characteristic is preferably the third cerebral ventricle. One infers a quantitative measurement of the intracranial pressure from at least two diagnostic characteristics, such as the diagnosis times, associated with the oscillogram. In a variant, one obtains a qualitative measurement of the intracranial pressure from the shape of the respiratory curve imposed on the wave path by the patient's respiration.
WO 99/26529 describes a fast Fourier transform processing unit applied to waveform frequency analysis (MHj) without corporeal movement and provides waveform analysis data (MKD). In parallel, a descendent wave extraction unit and a wave extraction unit linked to an incisure provide, respectively, descendent wave data (tide wave data, TWD) and incisure-linked dicrotic wave data (dicrotic wave data, DWD), which represent, respectively, a descendent wave and a incisure-linked dicrotic wave. A pulse evaluation unit then provides data relative to the pulse status (ZD) on the basis of TWD and DWD data, by means of which a notification unit establishes a report on the status of the pulse of the subject under consideration.
Also known is U.S. Pat. No. 4,893,630 describing equipment and a method for the analysis of the pressure in a living organ by a sensor delivering an analog signal, comprising an analog-digital converter and an analysis by Fourier transform to emit a distribution of the signal frequencies provided by the pressure sensors.
These different solutions are not completely suitable for the provision of particular information useful for the clinician.